Brushcutters, edge cutters and like work apparatus are used for many different tasks. For example, with the same work apparatus, one can mow a lawn as well as free the slope of a ditch or the like from plants. An ergonomic holding capability of the work apparatus contributes to making the work with the apparatus less tiring.
When working in approximately horizontal terrain, the guide tube of the work apparatus with the cutting tool at its end is held inclined to the surface being worked. To enable an operator to stand erect, handles are known which are attached to the guide tube and are angled up with respect to the guide tube or are configured in the form of a projecting bale handle having an approximately circular shape. When operating on banks or the like, a rotation of the work apparatus about the longitudinal axis of the guide tube is required in such a manner that the rotational plane of the cutting tool is aligned parallel to the surface of the bank. The handle, which projects upwardly above the guide tube, is at a spacing relative to the longitudinal axis of the guide tube and therefore relative to the center of gravity of the work apparatus. From this distance, a weight torque results about the handle and because of this weight torque, the operator is required to exert more force when the work apparatus is in an inclined position and this is more tiring. Handle arrangements are known wherein the handle is mounted close to the center of gravity which simplifies holding the work apparatus in an inclined position. However, this makes standing erect difficult when working on planar surfaces.
It is an object of the invention to make possible a simple manipulation of a work apparatus in a larger area of use.
The portable handheld work apparatus of the invention includes a brushcutter and an edge cutter. The portable handheld work apparatus includes: a drive motor assembly; a guide tube defining a longitudinal axis and having a first end connected to the drive motor assembly and having a second end; a drive shaft rotatably journalled in the guide tube; a work tool mounted at the second end of the guide tube; the drive motor connected to the work tool via the drive shaft for driving the work tool; a handle unit disposed in the region of the guide tube and arranged relative to the guide tube at an adjustable distance (a); a pivot assembly for pivotally mounting the handle unit so as to be pivotal about a pivot axis lying transversely to the longitudinal axis; the handle unit including a handle bracket and a resilient holder connected between the handle bracket and the guide tube; and, the resilient holder having a component extending in the direction of the longitudinal axis.
For this purpose, it is suggested to provide the handle with a resilient handle bracket holder between the handle bracket and the guide tube. The handle unit is pivotable about a pivot axis lying transversely to the longitudinal axis of the guide tube. The handle bracket holder extends with one component in the direction of the longitudinal axis of the guide tube and is especially configured to also be damping. In this way, the distance of the handle to the guide tube can be adjusted into an ergonomically favorable position in a pivot movement adapted to the utilization purpose then present. At the same time, a resilient support and damping of the handle is given acting approximately in the pivot direction. Because of the component of the handle bracket holder extending in the longitudinal direction of the guide tube, the resiliency and damping direction lies over the entire pivot range approximately transversely to the guide tube. Vibrations caused by the operation or force peaks, for example, when there is an impact of the cutting tool on a hard object, can be effectively kept away from the hands of the operator.
When working in level terrain, the handle can be pivoted upwardly away from the ground being worked which makes it possible for the operator to stand erect without tiring. When working on banks, the handle can be brought into a position close to the center of gravity and this supports a rotation of the work apparatus about the longitudinal axis thereof with only slight application of force by the operator. Because of the adjustable pivotable arrangement, the additional effort of exchanging various adapted handles is avoided. The extension component of the handle bracket holder in the longitudinal direction of the guide tube contributes to the condition that, when executing a pivot movement to adapt to the distance between the handle bracket and the guide tube, the position of the handle bracket in the longitudinal direction of the guide tube changes only slightly. A tedious readjustment of the longitudinal position in the region of the center of gravity is unnecessary. The handle includes an L-shaped, O-shaped or U-shaped handle bracket. With these forms, the number of various holding possibilities is increased and the possibility is presented to change the alignment of the work apparatus with less effort for a short time interval without pivoting the handle.
The handle bracket is connected at its respective ends to the guide tube via corresponding vibration-damping handle bracket holders whereby an adequately rigid connection of the handle bracket to the work apparatus for the precise guidance thereof is given in addition to an effective damping of vibrations. An inclined position of the handle bracket and therefore an improved ergonomic alignment is given by configuring the two handle bracket holders to have different lengths. Because of the different lengths of the two handle bracket holders, both have respectively different inherent frequencies whereby an effective damping of vibration is provided over an expanded frequency range. It has been shown to be advantageous to configure the handle bracket holders as flat components with the plane defined by the components to be approximately parallel to the longitudinal axis of the guide tube. On the one hand, an effective damping of loads, which act essentially perpendicular to the longitudinal axis of the handle tube, is given thereby. On the other hand, in the above-mentioned embodiment, the handle bracket holders are essentially rigid in the main movement direction of the work apparatus approximately parallel to the surface to be worked whereby the precision, with which the cutting tool can be guided, is improved.
The handle bracket holders are advantageously made of plastic and are especially each made as one piece with a holding socket formed thereon for the handle bracket. In addition to low manufacturing costs in large quantities, a high strength is simultaneously achieved in combination with excellent damping characteristics.
The handle bracket is preferably configured as a handle tube and is especially made of plastic or metal and advantageously enclosed with a plastic tube. With the tube, a high support capability is given while at the same time having low weight. The plastic tube improves the feel of the handle and generates an effective thermal insulation of the metal tube relative to the hand of the operator holding the same. With a configuration of the handle bracket in plastic, also forms of greater complexity are realized for improving the ergonomics.
It is advantageous to provide two stops which limit the pivot range of the handle. For this purpose, an arcuately-shaped slot or recess is provided on the handle which engages around a guide pin fixedly mounted on the apparatus. In this way, a free pivoting of the handle within a defined pivot range is made possible, on the one hand, and an excessive pivoting of the handle is, on the other hand, prevented. Such a pivoting can occur, for example, for an unwanted loosening thereof. The handle can advantageously be fixed in a binding and friction-tight manner with respect to its pivot axis. A friction-tight clamping connection can be provided with simple means and permits the continuous pivoting of the handle into a desired intermediate position adapted to the wishes of the operator. To prevent a slippage of the handle relative to its fixed work position, it can be practical to machine the engaging surfaces in the region of the pivot axis to have a higher coefficient of friction.
The handle is advantageously fixed to a clamping piece which engages around the guide tube and is there tightly clamped. In the loosened state, the clamping piece is rotatable about the longitudinal axis of the guide tube and is displaceable especially in the direction of the longitudinal axis of the guide tube. With this arrangement, the handle can be pivoted, rotated and displaced and is thereby universally adaptable to the ergonomic requirements of the operator or to the particular purpose of use. A sleeve and especially a sleeve made of a soft plastic is mounted between the clamping piece and the guide tube whereby, on the one hand, a reliable clamping is established and, on the other hand, damage of the guide tube is avoided. By fixing the handle on the clamping piece with the same clamping bolt with which the clamping piece is also fixed on the guide tube, the handle can be adjusted with a single grip by the operator simultaneously in several degrees of freedom by loosening the clamping bolt of the handle. To reduce the number of parts and therefore the manufacturing costs, the clamping bolt simultaneously defines the guide pin which engages in the above-described slot for limiting the pivot angle. By configuring the clamping bolt in the form of a screw with a wing nut rotatable thereon, the wing nut can be loosened or tightened without a tool whereby a rapid change between different adjusting positions of the handle is made possible.